Method of making a unitary connector structure

ABSTRACT

A method of making a unitary coaxial connector structure is accomplished by using a mold part having a center connector means in conjunction with a hollow metallic shell member of a coaxial connector. A mandrel means has one end secured to the mold part to hold the center conductor means centrally within the shell member. Another mold part is applied onto the other end of the shell member and it is filled to the other end of the mandrel means. Insulation material is introduced through an opening in one of the mold parts to fill the void within the shell member. The mold parts and mandrel means are removed from the shell member and the insulation material therein supports the center connector means in spaced relationship from the shell member and the removal of the mandrel means forms a bore in the insulation in communication with the center connector means.

Oct. 30, 1973 y W. L. SCHMACHER l METHOD OF MAKING A UNITARY CONNECTOR STRUCTURE 3 Sheets-Sheet l Original Filed Ooi. G, 1964 (3a. 3o, 1973 w. L. SCHMACHER 3,769,395

METHOD OF MAKING A UNITARY CONNECTOR STRUCTURE Original Filed Oct. 6, 1964 3 Sheets-S`neetv l N d INVENTOR. WILLIAM LubLoc-.J 5HuMAcHR I' '.OC 30, 1973 w. L. SCHMACHER METHODOI" MAKING A UNI'IARY CONNECTOR STRUCTURE Original Filed oct. e, 1964 3 sheets-sheet 3* MPa,

NVENTOR WILLIAM LuoLow scnuMAcHaR @Y wwf@ United States Patent O 3,769,395 METHOD OF MAKING A UNITARY CONNECTOR STRUCTURE William Ludlow Schumacher, Camp Hill, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Continuation of abandoned application Ser. No. 843,356, July 22, 1969, which is a division of application Ser. No. 401,546, Oct. 6, 1964, now Patent No. 3,317,882. This application Sept. 20, 1971, Ser. No. 182,113

Int. Cl. B29d 3/00; B29h 9/11 U.S. Cl. 264-102 4 Claims ABSTRACT OF THE DISCLOSURE A method of making a unitary coaxial connector structure is accomplished by using a mold part having a center connector means in conjunction with a hollow metallic shell member of a coaxial connector. A mandrel means has one end secured to the mold part to hold the center conductor means centrally within the shell member. Another mold part is applied onto the other end of the shell member and it is lled to the other end of the mandrel means. Insulation material is introduced through an opening in one of the mold parts to fill the void Within the shell member. The mold parts and mandrel means are removed from the shell member and the insulation material therein supports the center connector means in spaced relationship from the shell member and the removal of the mandrel means forms a bore in the insulation in communication with the center connector means.

CROSS-REFERENCE TO RELATED APPLICATION This application is a contnuationvof application Se?. No. 843,356, led July 22, 1969 (now abandoned) which in turn was a division of application Ser. No. 401,546, filed Oct. 6, 1964, now U.S. Pat. No. 3,317,882.

This invention relates to electrical connectors and more particularly to electrical connectors for use in a high voltage environment.

In high voltage applications, the conductor means carrying the high voltage has to be terminated at specific locations. These terminations have to be selected with care in order to preclude the occurrence of corona, since, if corona does occur, the efficiency of the high voltage application is diminished, and deterioration of the insulating medium at the terminations occurs.

AIt is, therefore, an object of the present invention to provide an improved electrical connector suitable for use with high voltages.

Another object of the present invention is to provide an electrical connector wherein the amount of air therein is reduced to a minimum.

An additional object of the present invention is to provide a high voltage electrical connector in which corona discharges do not occur.

A still further object of the present invention is to provide a high voltage electrical connector wherein termination of the center conductor is riveted in place.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration and principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

Patented Oct. 30, 1973 FIG. 1 is a cross-sectional view of the high voltage electrical connector connected to a coaxial cable means;

FIG. 2 is a partial sectional view of FIG. 1 but on an enlarged scale;

F'IG. 3 is a partial sectional view but on an enlarged scale of FIG. l;

FIG. 4 illustrates a type of coaxial cable onto which the present invention is to be connected;

lFIGS. 5-7 illustrate the steps by which the center conductor means of the cable means is connected to a center connector element; and

FIG. 8 illustrates a mold to form one-half of the connector.

Turning now to the drawings and more particularly FIGS. 1-4, there is illustrated a high voltage connector C for connection onto a coaxial cable means CM. This coaxial cable means is a high voltage cable and is manufactured by the Boston Insulated Wire and Cable Company, Boston, Mass., and comprises an outer insulation 1 surrounding a conductive braid 2 which, in turn, surrounds a semiconductive tape 3. A dielectric medium 4 is disposed between tape 3 and another semi-conductive tape 5 which, in turn, surrounds another conductive braid 6. A core 7 of insulation material is disposed within braid 6 and provides support therefor. Coaxial cable means CM is stripped in the manner set forth in FIG. l so th'at the l high voltage connector can be properly connected thereto.

High voltage connector C comprises two identical members 8 and 9 except that hollow metallic shell 10` includes a flange 12 at its large end while the large end of hollow metallic shell 11 includes thread 13. Another minor difference is that center connector element 14 in member 8 in which the center conductor is to be secured, has a female section 15 in which a male section 16 of similar center connector element 17 disposed in member 9 is to be disposed. Since members 8 and 9 are identical in construction, With the exception of the differences pointed out hereinabove, only one member will be described in detail.

Shell 10 is frusto-conical in configuration and has a flat section 18 near the small end thereof which extends parallel to the longitudinal axis. Flat section 18 merges into a tapered section 19 which terminates at the small end of shell 10. The inner surface of shell 10i is frustoconical 4to a point almost opposite the junction between sections 18 and 19 whereupon it merges into a flat surface 21 coaxial with the axis of shell 10.

Insulating material 22, which is preferably made of siliconerubber, or the like, is disposed in shell 10, and, as can be perceived, the outer surface of insulating material 22 has a conguration consonant with that of inner surfaces 20 and 21 of shell 10. A segment 23 of insulating material 22 extends outwardly beyond the small end of shell 10 and has a tapered surface 24 in alignment with the tapered surface of section 19 so that these tapered surfaces delne a frusto-conical configuration. A bore 25 of the'same diameter extends centrally through insulating material 22' and terminates at an abutting surface 2'6. Bore 25 is in communication with a frusto-conical opening 27 disposed in the large diameter end of insulating material 22. Entrance 28 of frusto-conical opening 27 is circular until it merges with frusto-conical opening 27, as seen in FIGS. 5-7. The surface of insulating material 22 between entrance 28 and the edge of the large diameter section of shell 10` is serrated defining spaced circular sections 2'9, 30 and 31. Sections 29 and 30' extend outwardly beyond the edge of shell 10 Iwhile section 31 is in alignment therewith. Part 32 of insulating material 22 also extends outwardly from the edge of shell 10. It is to =be noted thatsection 29 extends outwardly further than that of section 30, and, of course, section 30 extends outwardly further than section 31 from the edge of shell 10.

Insulating material 22 of member 9 includes sections 29 and 30 similar to circular sections 29 and 30 of insulating material 22 in member 8 but that section 31' extends outwardly from the edge of shell 11 further than corresponding section 31. Thus, the distance measured along circular sections 29 through 31 of insulating material 22 and circular sections 29 through 31 of insulating material 22 defines a path which is over lO inches in length.

4Center connector element 14 delines a frusto-conical configuration from female section 15 to the end thereof. A bore 33 of constant diameter extends centrally through center connector element 14 and is in communication with stepped-down sections 34 and 35, which, in turn, are in communication with the interior of female section 15. Entrances 36 and 37 of respective sections 35 and 15 are preferably beveled (see FIGS. 5-7).

Shells and 11, insulating material 22 and 22 and center connector elements 14 and 17 are assembled to form unitary structures. 'I'his is accomplished by securing center connector elements 14 and 17 and shells 10 and 11 to respective mold parts MP (see FIG. 8) having a configuration corresponding to that of circular sections 29-31 and 2931' by means of mandrels M which form bores and 25. Another mold part MPa is secured to shells 10 and 11 at their smaller end via the mandrels, and these mold parts MPa form segments 23 and 23'. The inner surface of shells 10 and 11 and the outer surface of elements 14 and 17 are preferably coated with a suitable bonding material while the mandrels are coated with a suitable release agent. Insulating material 22 and 22' is then introduced within shells 10 and 11 through one of the mold parts to form the desired configuration of the insulating material in accordance with that disclosed. After the insulating material has filled the void within shells 10 and 11, the insulating material is placed under vacuum in order to remove all air pockets and render it free of air as well as to remove all air from the interfaces between the shells and the insulating material and the center connector elements and the insulating material. When the insulating material has set, themold parts and mandrels are removed from shells 10 and 11 which are now unitary structures.

0f course, it is possible to mold insulating material 22 and 22' in its desired form and then insert this material within respective shells 10 and 11 with elements 14 and 17 being inserted in their proper places n the presence of bonding material on the shell and the elements to form the shell unitary structures.

In assembly, coaxial cable means CM is properly stripped in the manner illustrated in FIGS. 1 and 2. If dielectric material 4 is of the wrapped variety, it is preferable to wrap the stripped end thereof with a nylon monolament or the like in order to preclude any air gaps occurring therein. Grease is also applied to the forward portion of dielectric 4 to eliminate any air gap made possible by mismatch of dielectric 4 and abutting surface 26 of insulating material 22. The assembly of shell 10, insulating material 22 and center connector element 14 is pushed onto the coaxial cable means such that elements 4 through 7 pass into bore 25 of insulating material 22 and the tapered surfaces of sections 23 and 19 of insulating material 22, and shell 10' fits underneath semi-conductive tape 3 and braid 2, as shown in FIG. 3, with tape 3 terminating about halfway along the tapered surface of section 19. The stripped end of dielectric 4 engages surface 26 and braid `6 and core 7 extend into bore 33 with the end of braid 6 extending beyond entrance 36 while the end of core 7 terminates about midway of bore 33, as illustrated in FIGS. 2 and 5 through 7. As stated hereinbefore, the grease applied to the stripped end of dielectric 4 is disposed between surface 26 and the stripped end of dielectric 4 in order to compensate for any mismatch therebetween, to exclude any air therefrom, and to form a seal therebetween. This grease is 4 preferably of the monotlow type identified as Nebula EP-Z, which is manufactured by the Standard Oil Cornpany of New Jersey.

As shown in FIG. 6, the inner sharp edge of center connector element 14 extends within semi-conductive tape 5 and dielectric 4 so that semi-conductive tape 5 is in engagement with the outer surface of center conductor element 14.

A Pop rivet assembly 38 of the type manufactured by United Shoe Machinery Corporation, Shelton, Conn., comprises a tubular member 39 having at one end an outwardly-directed flange 40 and an inwardly-directed flange 41 at the other end. Shank 42 of a pin 43 is disposed within tubular member 39 and extends outwardly from flange 40. Pin 43 includes a head 44 disposed adjacent ange 41, and area 45 between shank 42 and head 44 is of less diameter than that of shank 42.

Pop rivet assembly 38 is inserted within braid 6, stepped sections 34 and 35 and into bore 33 of center connector element 14, as illustrated in FIG. 6. With the Pop rivet assembly in position within center connector element 14, a conventional Pop rivet actuating tool (not shown) is placed into engagement with the part of shank 42 extending outwardly from flange 40. Upon actuation of the Pop rivet actuating tool, end 43 moves relative to center connector element 14 causing head 44 to move completely within tubular member 39 and coming to a wedged position of rest therein within stepped section 35, as illustrated in FIG. 7.

The action of head 44 moving within tubular member 39 causes flange 40 to be seated within beveled entrance 36, moves the part of tubular member 39 disposed in bore 33 outwardly against braid 6 disposed in bore 33 thereby spreading braid 6 against bore 33 and the interface between bore 33 and stepped section 34, and, at the same time, shortening the length of tubular member 39. The continued movement of head 44 within stepped section 34 moves the tubular member, in this section, outwardly against braid 6 causing the braid to be wedged against stepped section 34 effecting excellent electrical and mechanical contact. At the interface between stepped sections 34 and 35, head 44 then comes to rest with parts disposed in stepped sections 34 and 35, and, in doing so, moves the part of tubular section 39 therein outwardly against braid 6 causing the braid to be wedged against stepped section 35. After head 44 has moved to its position of rest at stepped sections 34 and 35, as illustrated in FIG. 7, shank 42 is removed from head 44 by additional tensile force which causes shank 42 to break at area 45 so that shank 42 does not remain a part of the Pop rivet assembly after the Pop rivet has been secured in position. The wedging action of tubular member 39 against braid 6 becomes progressively increased from bore 33 to stepped section 35 whereat it reaches its maximum wedging action. The wedging action of flange 40 against braid 6 at entrance 36 is also excellent. Thus, as can be discerned, there has been disclosed a unique connection of the center braid 6 onto center connector-element 14 by a rivet means to provide an excellent electrical and mechanical connection external of the critical high voltage field where sharp projections or ar'of any amount cannot be tolerated.

Now that braid 6 has been effectively connected to center connector element 14, braid 2 and tape 3 are affixed in intimate contact with the tapered surfaces of sections 19 and 23. A suitable insulating material 47, such as, insulating tape is wrapped tightly over braid 2 and semi-conductive tape 3 so as to exclude any air pockets. Clamp 46 of any desirable form is used to affix braid 2 to flat section 1'8 of metallic shell 10, thus, providing a positive electrical connection aswell as providing mechanical strength. Additional wrapping of insulating tape 47 is used to cover the clamp and braid ends. If desired, a conductive paint or grease may be spread on the surface of cable dielectric medium 4 and surface 24 to aid the exclusion of air during this nal assembly operation. Also, if desirable, insulating material 47 may be accomplished in any desirable fashion such as, slipping a premolded boot having a contoured inner surface so as to provide air exclusion from between the surfaces of 4 and 24 and tape 3. The same procedure, as outlined hereinbefore, is followed in connecting the coaxial cable means to the elements of member 9.

After the coaxial cable means has been connected to the elements of members 8 and 9 of the connector member, members 8 and 9 are ready to be brought into engagement to interconnect shell 10 with shell 11 and center connector element 14 with center connector element 17'. After members 8 and 9 have been brought into engagement, circular sections 29 through 31 of insulating material 22 mesh with circular sections 29' through 31' of insulating material 22', and male section 16 of center connector element 17 is disposed within female section 15 of center connector element 14. Beveled entrance 37 of female Section 15 and semi-circular segmented spring lip 48 on male section 16 facilitate the insertion of male section 16 within female section 15. The diameter of semi-circular spring lip 48 is slightly larger than that of the interior surface of female section 15 so that an excellent mechanical and electrical connection is obtained between center connector element 14 and center connector element 17.

In order to draw the edges of members 8 and 9 into a tightly abutting relationship, as illustrated in FIGS. l and 2, a threaded coupling member 49 engages flange 12 of shell 10 and threaded section 13 of shell 11, and, upon tightening coupling member 49 onto threaded section 13, members 8 and 9 are brought into tight engagement. At this position of engagement, circular sections 29 through 31 are tightly meshed with circular sections 29 through 31', which excludes all air therefrom and male section 16 is properly seated within female section 15. Thus, the path from engaged shells 10 and 11 to engaged center connector elements 14 and 17 is along tightly meshed circular sections 29 through 31 and 29 through 31', and is over 10 inches in length, as mentioned hereinbefore. As can be perceived, the points of change in the direction of the path are not in alignment so that these points which are parallel with the voltage stress between center connector elements 14 and 17 and outer shells 10 and 11 will not have any cumulative effect. The points of circular sections 29 and 29 have been arranged to be the furthermost from the center line of the connector in order to place them at a point of lower voltage stress in the eld because the highest voltage stress occurs at the surface of inner tape 5 and center connector elements 14 and 17.

The electrical connection between male section 16 and female section 15 of the center connector elements is made interiorly of the electrical eld so that the space therebetween which contains air does not effect this connection. Semi-conductive tapes 3 and 5, disposed on each side of dielectric medium 4, obviate the occurrence of any air between braids 2 and 6, since they are in intimate contact with this dielectric medium. Dielectric medium 4 ts snugly within insulating material 22 so that no air is present within the connnector. If the surface of dielectric medium 4 is not smooth, a grease is used to ll any possible voids.

As can be discerned, there has been disclosed a novel coaxial cable connector for connnection on coaxial cable means carrying high voltage and including a unique connection for the center conductor means.

It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it should be emphasized that the particular embodiment of the invention, which is shown and described herein, is intended as merely illustrative and not as restrictive of the invention.

What is claimed is:

1. A method of fabricating a coaxial connection comprising the steps of (a) providing an electrically conducting hollow shell having open ends with both a mandrel having a shoulder thereon and an electrical, contact element interiorly of said hollow shell, said contact element having a bore therethrough being removably postioned on one end of said mandrel in abutting engagement with said shoulder;

(b) providing a mold part on one open end of said hollow shell, removably securing said mold part to said mandrel with said electrical contact element being sealingly secured between said shoulder and said mold part;

(c) connecting another mold part to another end of said mandrel, said another mold part having entrance means therein in communication with the interior of said hollow shell;

(d) filling said hollow shell through said entrance means with moldable insulation material, said material permanently conforming to the shape of said interior surface of said hollow shell, and being affixed to said electric contact element;

(e) subsequently removing said mold parts from said insulation-filled shell and from engagement with said mandrel and electric contact element; and

(f) removing said mandrel from engagement with said electrical contact element and from the interior of said shell to provide a bore through said permanently conformed insulation material, said bore being aligned with said bore in said electrical contact element thereby allowing for reception of a center conductor and a surrounding dielectric medium of a coaxial cable.

2. The method as recited in claim 1, and further including the step of: coating the interior surface of said hollow shell with a mold bonding agent prior to the step of providing said mandrel interiorly of said hollow shell.

3. The method as recited in claim 1, and further including the step of: coating the contact element with a bonding agent prior to the step of positioning said contact element on said mandrel, and the step of introducing insulation material interiorly of said hollow shell further includes the step of bonding said insulation material to said connector element by said bonding agent.

4. The method as recited in claim 1, wherein the step of conforming the shape of said insulation material further includes the step of applying a vacuum to said hollow shell interior in order to conform the shape of said insulation material to the shape of said hollow shell interior without the presence of air pockets.

References Cited UNITED STATES PATENTS 2,660,151 11/1953 Smith et al 18--36 X 2,864,130 12/1958 Beare 264-262 X 2,958,101 11/1960 Guggenheim et al. 264-278 X Re. 26,491 11/ 1968 Colbert 18-36 X 2,561,351 7/1951 Fentress 264-275 X ROBERT F. WHITE, Primary Examiner J. H. SILBAUGH, Assistant Examiner U.S. Cl. X.R. 

